1. Field of the Invention
The present invention relates to a mounting structure for the photographic element of a camera which uses a semiconductor element that performs photoelectric transfer, such as a CCD (Charge Coupled Device), as its photographic element.
2. Description of the Related Art
In recent years, there has been rapid development in the field of video cameras that include an optical lens and photographic elements.
FIG. 1 is an exploded perspective view of the conventional mounting structure used to hold the photographic element in a video camera. This mounting structure is composed of a chassis 101 for mounting the optical lens, a substrate 103 for mounting the photographic element 102, and four screws 104-107 for screwing the substrate 103 to the chassis 101.
The chassis 101 features an aperture 108 into which the photographic element 102 is inserted. Connected to the aperture 108 on the side of the chassis 101 that faces away from the substrate 103, a lens cover mounting 109 is formed with a thread in its outer surface. Four substrate supports 110-113 for supporting the substrate 103 are formed at the corners of the chassis 101 on the substrate 103 side. These substrate supports 110-113 feature threaded holes 114-117 for the screws 104-107.
Four holes 118-121 are drilled into the substrate 103 at positions corresponding to the threaded holes 114-117.
FIG. 2 is a cross-section, taken parallel to the optical axis C-Cxe2x80x2 of the lens, of the mounting structure of FIG. 1 that mounts the photographic element 102.
The mounting method for the photographic element 102 is described below with reference to FIGS. 1 and 2. This photographic element 102 is housed by the protective package 201. Elements such as the pins 202 and 203 of the photographic element 102 are soldered onto the substrate 103 so that the center of the substrate 103 is aligned with the center of the photographic element 102. Here, the solder 204 and 205 may be replaced by sockets fixed to the substrate 103, with the pins 202 and 203 being inserted into the sockets to hold the photographic element 102. After this, screws 104-107 are inserted into the holes 118-121 in the substrate 103 and are screwed into the threaded holes 114-117 of the chassis 101, and, with the substrate 103 loosely attached to the chassis 101, the optical lens cover holding the optical lens is attached to the chassis 101. The photographic element 102 is then attached to a measuring apparatus and while shooting a test pattern or the like, the substrate 103 is repositioned so that the center of the photographic element 102 coincides with the optical axis of the lens. When this position is found, the screws 104-107 are tightened to attach the substrate 103 to the chassis 101.
This mounting structure for photographic element 102 has a major drawback in that it is difficult to solder the photographic element 102 in the dead center of the substrate 103. Also, a considerable amount of time is required to adjust the position of the substrate 103 with the screws 104-107 loosely attached so that the center of the photographic element 102 coincides with the optical axis of the lens, making the assembly process troublesome and requiring special skills. Such adjustment also requires the use of special equipment.
The mounting structure for the photographic element described above suffers from another drawback in that it is necessary to mount a metal cover to reduce the amount of radiation generated by the photographic element 102 and the substrate 103 that would otherwise escape to the periphery.
In view of the stated problems, it is a first object of the present invention to provide a mounting structure for a photographic element of a camera that does not require equipment for adjustment of the optical axis and that easily adjusts the optical axis.
A second object of the present invention is to provide a mounting structure for the photographic element of a camera that reduces the effects of external radiation on the photographic element and plate and reduces the amount of radiation generated at the photographic element and plate that would otherwise escape to the periphery.
The stated first object can be achieved by a mounting structure for a photographic element of a camera, including: a photographic element package (a) on whose main surface a light-sensitive surface of the photographic element is arranged, (b) in whose side surfaces two standard surfaces that meet at a predetermined angle are formed, and (c) where a center of the light-sensitive surface of the photographic element is defined as a point which is a first offset amount from one of the standard surfaces and a second offset amount from another of the standard surfaces; a chassis (a) provided with a lens holding unit and an aperture which is located behind a lens that is set in the lens holding unit, (b) formed so that an aperture brim of the aperture is larger than the photographic element package to allow the photographic element package to move when inserted into the aperture brim, (c) has two contact surfaces that meet at the predetermined angle formed in the aperture brim, and (d) has the two contact surfaces positioned so that respective distances from the two contact surfaces to an optical axis of the lens are equal to the first offset amount and second offset amount of the light-sensitive surface of the photographic element; and a mounting member (a) which mounts and attaches the photographic element package onto the chassis in a state where the main surface of the photographic element package faces the lens through the aperture in the chassis and where the two standard surfaces are aligned with the two contact surfaces, (b) which includes an energizing unit, and (c) the energizing unit energizes the photographic element package in a direction perpendicular to the optical axis of the lens, as a result of the photographic element package being mounted onto the chassis, so that the two standard surfaces of the photographic element package firmly press against the two contact surfaces of the chassis.
With the stated construction, the standard surfaces of the photographic element package firmly press against the contact surfaces of the chassis so that the center of the light-sensitive surface of the photographic element is positioned on the optical axis of the lens. As a result, equipment for adjusting the optical axis of the lens is unnecessary and operations for centering the light-sensitive surface on the optical axis can be completely eradicated.
Here, a circuit board for a circuit that processes a signal generated by the photographic element may be provided on a back of the photographic element package, with the circuit board being integrated with the photographic element package via a connecting member, wherein the chassis may have at least one support part for supporting at least one part of the circuit board, and wherein the energizing unit of the mounting member may be an elastic member which, when the photographic element package is mounted onto the chassis, directly applies a force to side edges of the circuit board.
With the stated construction, the photographic element package will definitely be able to move within the aperture brim, and the standard surfaces will definitely press against the contact surfaces.
Here, the mounting member may have at least one pressing member for pressing the side edges of the circuit board onto the support part from behind when the photographic element package is mounted on the chassis.
With the stated construction, a circuit board can be attached to the chassis.
Here, the elastic member may be composed of a first spring for pressing the circuit board in a direction so that one of the standard surfaces firmly presses against one of the contact surfaces and a second spring for pressing the circuit board in another direction so that another of the standard surfaces firmly presses against another of the contact surfaces.
With the stated construction, the two standard surfaces will definitely press against the two contact surfaces.
Here, at least one fastening may be provided on the mounting member, and wherein at least one engagement part, which engages the fastening when the mounting member is moved parallel to the optical axis of the lens, may be provided on the chassis.
With the stated construction, the circuit board will be held sandwiched between chassis and the mounting member.
Here, the photographic element may be an area sensor composed of a CCD (Charge Coupled Device), and the photographic element package may be a construction where side and rear surfaces of the area sensor are covered in one of a ceramic material and a resinous material.
With the stated construction, it is no longer necessary to adjust the optical axis of a photographic element composed of a CCD.
The stated second object can be achieved when the mounting member is a case construction which entirely covers side and rear surfaces of the photographic element package, the case construction being composed of a back plate and side plates at sides of the back plate which protrude from the back plate, and the back plate and side plates being formed of a material that acts as a shield to electromagnetism, wherein the chassis is also formed of a material that acts as a shield to electromagnetism.
With the stated construction, unwanted external radiation can be prevented from entering the photographic element from outside.
Here, at least one fastening may be formed in the side plates of the mounting member, and at least one engagement part, which engages the fastening when the mounting member is moved parallel to the optical axis of the lens, may be provided at at least one corresponding position on the chassis.
Openings, into which front tips of the side plates of the mounting member can be inserted parallel to the optical axis of the lens, may also be provided in the chassis, wherein the fastening formed in the side plates may be an engagement hole, and wherein the engagement part may be an engagement peg which is provided inside at least one of the openings in the chassis.
With the stated construction, the photographic element package can be held enclosed within the chassis and the mounting member.
Here, a circuit board for a circuit that processes a signal generated by the photographic element may be provided on a back of the photographic element package, with the circuit board being integrated with the photographic element package via a connecting member, wherein the chassis may have at least one support part for supporting at least one part of the circuit board, wherein the energizing unit may be an elastic member which is provided on an inside of at least one of the side plates of the mounting member, and wherein the energizing unit may directly apply a force to side edges of the circuit board when the photographic element package is mounted onto the chassis.
With the stated construction, radiation generated at the photographic element and plate can be prevented from escaping to the outside.
Here, the first and second springs may each be composed of a plate spring which increases a force on the circuit board perpendicular to the optical axis of the lens as the side plates of the mounting member approach the openings in the chassis.
With the stated construction, the standard surfaces will come into complete contact with the contact surfaces when the photographic element package is mounted onto the chassis.
Here, at least one guide plate, for guiding the side plates of the mounting member into the openings, may be formed on the chassis, wherein each guide plate is positioned outside one of the openings.
With the stated construction, the mounting member can be easily mounted onto the chassis.
The stated first object can also be achieved by a mounting structure for a photographic element of a camera, including: a photographic element package (a) on whose main surface a light-sensitive surface of the photographic element is arranged, (b) in whose side surfaces two standard surfaces that meet at a predetermined angle are formed, and (c) where a center of the light-sensitive surface of the photographic element is defined as a point which is a first offset amount from one of the standard surfaces and a second offset amount from another of the standard surfaces; a chassis (a) provided with a lens holding unit and an aperture which is located behind a lens that is set in the lens holding unit, (b) formed so that an aperture brim of the aperture is larger than the photographic element package to allow the photographic element package to move when inserted into the aperture brim, (c) has two contact parts, for touching the two standard surfaces of the photographic element package and positioning the photographic element package, formed in the aperture brim, and (d) has the two contact parts provided at predetermined relative positions to an optical axis of the lens so that when the two contact parts touch the two standard surfaces, a center of the photographic element is aligned with the optical axis of the lens; and a mounting member (a) which mounts and fixes the photographic element package onto the chassis in a state where a main surface of the photographic element package faces the lens through the aperture in the chassis and where the two standard surfaces are aligned with the two contact parts, (b) which includes an energizing unit, and (c) the energizing unit energizes the photographic element package in a direction perpendicular to the optical axis of the lens, as a result of the photographic element package being mounted onto the chassis, so that the two standard surfaces of the photographic element package firmly press against the two contact surfaces of the chassis.
With the stated construction, equipment for adjusting the optical axis of the lens is unnecessary and operations for centering the light-sensitive surface on the optical axis can be completely eradicated.
Here, each of the two contact parts may be a surface.
Also, each of the two contact parts may be corrugated in form and may touch a corresponding standard surface in at least two places.
With the stated construction, the center of the light-sensitive surface of the photographic element can be aligned with the optical axis of the lens.